Method of producing a constant magnetization by means of alternating currents.



PATENTED MAY 3, 1966 M. G. A. LATOUR.

METHOD OF PRODUCING A CONSTANT MAGNETIZAEIQX BY MEANS OF ALTBRNATING GURRENTS.

APPLIGATXQH FILED KEPT. 10, 1904.

l llnnil-llllitti Inve ntor: Marius C. A. Lento I llflllil'li ll Witnessesw; um-

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' UNITED STATES MARIUS c. A. LATOUR, or PARIS,

ZPATEXI. ()lll lOlil.

FRANCE, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

METHOD OF PHODUClllG ACONSTANT MAGNETIZATlON BY NEWS OF ALTERNATING CURRENTS.

Specification of Letters Patent.

Patented May 1, 1906.

Application lilcli September 10, 1904 Serial No. 228,943.

Currents, of which the following is a specification.

' My invention relates to the excitation of magnetic circuits; and its object is to provide a novel method of producing aunidircctionai constant flux in the magnetic circuit by means of alternating currents- Mg invention is based ontthe mathernatical trut expressed by the equation sinlo', +'cos.' a I.

Iapplication of this formula has heen made utin-and Le Blane in the invention dis cosed in their patent, No. 572,510, issued December 1, 1896, In this patent they show means for converting alternatin currents into direct current as follows: y means of alternating current sinusoidal flux is (produecd in a magnetic circuit, thereby in ucing a sinusoida electromotive force in a secondary winding carried b said magnetic circuit, and the-number 0 effective turns of that seconds windin issimultanoousl v ried in accor ance wit the same sine 0- tion as that by which the electromotivc force varies. Since the volts per coil vary with the sine function and since the number of coils in circuit va with the same sine function, the resultant electromotive force varies as a sine function. Bj' similarly producing V in a second winding .a voltage varying as a cosine'as, for instance, by exciting it by means of a flux displaced ninety degrees from thatwhich excites the first winding and also by va ingthe efiective turns in accordance witht e cosine function and b y connecting the two windin s in series the electrometive forces are ad ad, and a, resultant constant unidirectional voltage is obtained in accordance with the formula. it isshown in the above-mentioned patent that the theory is not limited to the comicnation of the squares of two sinusoidal functions difierizzg in phase byninety degrees, but is applicable in general to any polyphasc arrangement. By connecting in series any number of voltages, each varying as the sins of the phase angle of one of a number of Furthermore hases, a constant unidirectional voltage will e obtained.

, By mi invention} make a novel app ication of t e theory briefly outlined above and d closed in full in the patent referred to. By

m invention a number of superimposed fluxes are reduced in a single magnetic cirsuit, each ux varying as a. sine of the hose angle of one of a plurality of phases. iii accordance with the theory I thcreh obtain a constant unidirectional flux whic may' be utilized for the some purposes as a similar flux as ordinarily produced by direct current.

My invention t on consists in the method of producing a constant magnetization which consists in producing a plurality of superimposed fluxes each varying with the sisal-unation of the phases.

More specifically considered, my. invention 7 consists in the method of producing a constant magnetization in a magnetic circuit which consists in supplying to the exciting winding or windings thereof polyphase vol-.

tagcs and simultaneously varying the effective number of turns connected to each phase of phase angle of one of a number of=- the impressed voltage in accordance with the variation of the sins of the phaseangle of said voltage.

My invention'will best be understood by reference to the accompanying drawing, which shows diagrammatically an arrange merit adapted for producing a um'directionhl magnetization in accordance with my inventron.

In the drawing, A represents a portion of a magnetic circuit on which is placed a winding formed in a number of sectioned to a, one-half of the sections being wound oppositely to the other half and the whole connected in a closed winding. The closed winding formed by these sections is tapped zit-points between adjacent sections to the se ments of a six-part commutator C. B E coil B B represent revolving brushes hearing on the conunutator. Evidently the llull'llltl of olfestive turns of thewinding connected in circuit with the brushes will vary during the retation of the brushes.

Considering the number of turns in each section, it will be remembered that in order to obtain a sinusoidal variation of the nuns be! of effective turnsina circuit the successive coils or sections should contain a number of turns set forth in the patent. above. referred to by the following expressions: No. of turns s or it, /he prmlueed eorrespondin 2 71 roll I: sm. (u/+ No. of turns in third 4 1r cull k sin. (a ,&c., k bomgaoonstant and nhoiug the number of coils.

Now in order to tako a simple example let u I, u 1: t), and k f 2. Substituting these values in the oxpressionsgivon ahove, the number of turns in each coil or section will hen-s lollowsz lfl, l, -l, 2, i. It is this arrangement that. is shown in the drawing, the negative signs being taken care of by reversing the direction of winding of these sections. Ofcourse in order to geta close approxinuttion to a'sine function a. greater number of sections should be stdccted; but the arranmuuent shown will serve for the purpose of illustration. It will be seen that the two sections of two turns each are shown in heavier lines than the other sections. The purpose is to indicate that the turns are of greater eross-section. 'lhe several sections are ireferablv so woundthatthe resistances of ali the sectionsnre approximately equal. so that the ohmic resist-mice of the circuit will nothe Varied as the brushes 1H; revolve in the oouunutator (.3.

Now it the brushes B l! are placed, as shown. on tlwcouuuutator. it. will be seen that. the current entering and leaving the brushes divides, half going through each half of the sections and the current in all tho sections assisting in producing the magnetization that is. the total number of ampere-turns is equal to H, I being the current entering at the brushes. ll' this current is analternnting current derived from one phase of the twohase source l the ampere-t urns at any instant will be equal to 41 sin. a. where l is the maximum value of the current entering the brushes. .\ow if the brushes B B are revolved ius \'m'hronisui with the alternation of the currents entering the brushes the effect ive number of turns traversed by the current entering the lu'ushes \vill also vary. as sin. a. and the resultant ampere-turns at an instant may be ex iressed bv 41 sinfo. Now it a second pair o brushes B B is placed on the muumntutor. displaced ninety degrees from the brushes B B, and if a current is sent through this second set. derived from the other phase of source I) and displaced in ihase ninety do 'rees from the current sent through the brushes BB, :1 second flux would to the ampereturns. rhe ell'eetive value 0 which at any in stunt aould bee ual to 41 cos.a and the resultant flux woul he equal to 4]-that is,the flux would be constant and tmidirectional. Obviously this flux may be used for any purpose whatever for which a similar flux produced by direct current might be om iloyod. and, furthermore, myinvention is notiimitod to the. use of two-phase currents supplied to the winding throu h a two-phase. arrangement of brushes. i olyphnsu current may be supplied to the winding through a suitable arrangement ol' brushes to produce the desired magnetization. That any other polyphaso arrangement is equivalent. to the. twophase arrangement shown will. be obvious to those skilled in the art and is, moreover, lull explained in Patent No. 572,510, above. referred to. 7 v

Moreover, it is not esscn tial tha'tpolyh pose currents should be supplied to the coin "tutor tor. li simple alternating current is supplied to one set. of brushes and t/he other circuit is short-oirc'uited instead of being eonuccted to a second phasc, a current will llow through this short circuit/due to iinluctiou in the exeitin -winding; and the magnetomotive force. tie to this current will vary approxinmtely with a sinc" function and with the maguetomotive l'orce due to alternating current supplied to the. other brushes will produce a substantially constant llux in the magnetic circuit, though this method is not as ellicient as the pol vphase excitation. For my invention it is only essential to iroduce in the uui-gnetie circuit a. plurality o magnetomotivc forces each varying as the St uare of a sine function, and it is immaterial whence the currents irt'iducing these 1nagnetomotive forces are r erived.

Obviously it makes no dill'erencc whether the commutator and exeit-ing-winding are,

statiouarv and the brushes revolve, or vice versa. be number of sections of the winding may be varied. as desired, the greater the number of sections the closer the approximation to a sine variation. Furthermore, although a single whaling is suiliciont for produring a constant tlux a greater number of windings may be used. if desired.

What 1 claim as new, and desire tosee-ure Letters Patent ol' the United States. ist. The method of producing a, substantiallvconstant nuidirmtional flux in a. mag netic circuit. which consists in producing therein a plurality of magnetomotive forces ouch varying as the square oi a sine function.

.2. The method of producing a. substantially constant unidirecliomil flux in a magnetic circuit, \vhich consists inproducing therein a pluitility of superimposed magnetomotive force's varying respectively as the squares of the sines of the phase angles of a polyphase system.

3. The method of producing a. substantially constant unidirectional llux. in a. ma netio cireuit provided with an exeitiiw-win ing, which consists in impressing po yphasc 'ing'the voltages on said winding and var number of efiective turns connects to each phase of said voltages at the same rate as that at which the voltage of that Phase vames.

4. The method of producing a. substantiaiiy constant unidirectional flux in a ma netic circuit provided with an exciting-win which consists in impressing on said wmding pobgihase voltages and varying the number of e active turns connected to each phase of said volts as as the sine of the phase angle of the v0 tage of that phase.

5. The method of producing a substantially constant unidirectional flux in a ma netic circuit provided with an exciting-win ing, which consists in cansingepolyphase currents toflow in said winding and vs g the number of efiective turns traversed h gr each of said currents in accordance with the variation in thecurrent itself.

6. The method of producing a substantially constant unidirectional flux in a ma netic circuit provided with an exciting-win ing, which consists in causing polyphase currents to flow said winding and verging the 5 number of efiective turns trave gdd y each of said currents in accordance with the varianumber of efiective turns traversed y each 7 current in accordance with the sins of the phase angle ofsaid current, whereby a plurality of magnetomotive forces are produced each varying with the sine of the current a which produces it.

In witness whereof I have hereunto set rny hand t 's 8th day of September, 1904.

MARIUS cl A. LAToU i' Witnesses: v p

' G C. HOLLISTER, V

HELEN Onronn. 

